Mourning Pearls

Often carried by Merfolk, mourning pearls echo the haunting songs that the merfolk sing. Sometimes they give them as gifts to humans, who value these things for their haunting beauty both aesthetic and melodic. Some pearls are used as jewelry worn by widows, while others are used in music boxes to eternally play their haunting melodies.
When multiple Mourning Pearls are put close together they harmonize, creating beautiful tapestries of music that can bring almost anyone to tears. If one of these pearls is damaged, its music will be out of tune. The more damaged the pearl, the more out of tune the music becomes. If it manages to be completely destroyed, it will let out an earsplitting shriek that can cause anyone nearby to become deaf.
These pearls are considered incredibly valuable by most and are not used as currency in The Pearl Market, which uses regular pearls as currency.

These pearls are often worn as jewelry and adorned with smaller regular pearls.